Interossei of the Hand Under the Skin, Anterior View

Description

Beneath the palmar skin of an adult male hand, the interossei occupy the intermetacarpal spaces as tapered muscle bellies hugging the shafts of the metacarpals. Palmar interossei lie more on the volar surfaces and tend toward the medial or lateral sides of the metacarpals depending on their digit of insertion, while dorsal interossei sit deeper and more centrally between adjacent metacarpals, with tendon slips coursing distally toward the bases of the proximal phalanges and extensor expansions. Superficial to this layer, the flexor tendons (flexor digitorum superficialis and profundus) track toward the digits, and a branching palmar vascular network, including contributions to the superficial palmar arch and common palmar digital vessels, spreads distally across the metacarpal heads. Small structures, tight quarters. Interossei anatomy matters when you are localizing intrinsic muscle dysfunction: the deep branch of the ulnar nerve innervates both palmar and dorsal interossei, so loss of finger abduction and adduction (dorsal and palmar interossei, respectively) points away from a median neuropathy and toward Guyon canal compression or a deep ulnar lesion in the palm. The anterior, under-skin perspective also helps when planning incisions for metacarpal fracture fixation or drainage of deep palmar space infections, where careless dissection can violate the palmar arches or denervate the intrinsic compartment and leave persistent weakness or clawing. Use this artwork in gross anatomy and hand surgery teaching to connect metacarpal osteology with intrinsic muscle compartments, and in rehabilitation, neurology, or EMG references when explaining ulnar-innervated intrinsic patterns in grip and pinch. It also fits operative consent materials for ulnar nerve decompression, tendon transfer planning, or vascular injury discussions in the palm. Anatomical accuracy verified by SciePro's Medical Advisory Board.